Mechanistic Insights into PFAS Adsorption on Microplastics: Effects of Contaminant Properties and Water Chemistry.

Implications of water chemistry on ozone nanobubble-based advanced oxidation processes.

The impact of source water chemistry on the efficiency of groundwater arsenic (As) remediation systems in real-world conditions remains under-investigated. To contribute to addressing this gap, the aim was to systematically evaluate removal efficiency of field-installed As remediation systems (n = 98) in Bihar, India from locations with varying groundwater chemistry (e.g. As: < 1 - 100 μg/L; Fe: < 1 - 1000 μg/L; P: 10 - 600 μg/L; [Fe]−1.8[P][As] molar ratio: -900 - 300). Sampled systems varied in type (e.g. source switching, pump and treat), technology (e.g. filter, sorption, membrane), ownership (e.g. private, public) and implementation setting (e.g. household, community). Removal of As and other contaminants (Mn, Fe, F- and NO3-) varied widely (negative to ~ 100 %). Notably, ~ 90 % of the installed systems had inlet As below the 10 μg/L WHO provisional guideline, highlighting the need to install remediation systems where their need is more indicated. Relative As removal was negatively correlated (p < 0.01) with inlet As (ρ = -0.37), Fe (ρ = -0.51), [Fe]/[As] (ρ = -0.41), [Fe]/[P] (ρ = -0.51) and [Fe]−1.8[P][As] (ρ = -0.54); but no significant relationships were observed with those parameters if split by technology (presence/absence of reverse osmosis (RO) membrane). Privately owned and RO-based remediation systems had higher As removal than other systems, noting however potential confounding factors of differing technical specifications and/or system operations. To ensure effective and sustainable interventions, remediation system selection in groundwater As affected regions should adequately consider factors including system operation and maintenance and technology type in addition to geochemical suitability.

Water quality controls on toxic DBPs: A global multivariate assessment of THMs, HAAs, and HANs.

Associations between Molar-Incisor Hypomineralisation and drinking water and groundwater parameters in Lower Austria: Results from an observational study.

The proliferation of antibiotic resistance genes (ARGs) represents a critical global health threat, with wastewater treatment plants (WWTPs) identified as major hotspots for resistance amplification and dissemination. While bacterial conjugation has been extensively studied, bacteriophages are emerging as significant but underestimated vectors for ARG transfer via transduction. We hypothesize that phages are capable of withstanding disinfection and exploiting diverse bacterial hosts in receiving environments, thereby functioning as active vectors of ARG dissemination rather than passive genetic reservoirs. Meta-analysis of disinfection efficacy data (n = 79 experimental observations, 6 technology categories) reveals significant differences in log₁₀ reduction across disinfection technologies (Kruskal-Wallis: H = 25.96, df = 5, p < 0.0001). Ozonation was significantly more effective than chlorination (p < 0.001), membrane processes (p = 0.003), UV irradiation (p = 0.005), and PAA/thermal treatment (p = 0.010). Phage persistence in receiving waters follows a 1-4week timeline modulated by temperature (Q₁₀ ~ 2-3), solar UV, and water chemistry. Broad host range phages have the potential to transfer ARGs to environmentally dominant genera (Aeromonas, Pseudomonas, Vibrio), and sub-inhibitory antibiotics may induce prophages and enhance bacterial competence, creating synergistic conditions that could accelerate resistome evolution. This review underscores the need for integrated approaches combining phage-targeted disinfection with ecological monitoring to effectively restrain the spread of antibiotic resistance.

Introduction Surface waters in tropical coastal regions are essential for domestic, agricultural, and industrial uses, yet they are increasingly threatened by anthropogenic pressures and seasonal variability. Methods This study evaluates the spatio-seasonal variability of surface water mineralization in the Bonoua region (Southeastern Côte d’Ivoire) based on two sampling campaigns conducted during the rainy and dry seasons across rivers and lagoons. A total of 28 samples (14 rainy season; 14 dry season) were analyzed for physicochemical parameters, major ions, nutrients, and trace metals. Hydrochemical facies were determined using Piper diagrams, mineralization processes were interpreted using Gibbs diagrams and ionic ratios, and multivariate relationships were examined through Principal Component Analysis (PCA). Water quality was further assessed using the Modified NSF-WQI. The results reveal pronounced seasonal contrasts. Results Electrical conductivity increased by +107.8%, reaching 1,240 μS cm −1 at site L3 during the dry season, while total dissolved solids increased by +118.1%. In contrast, Fe (−46.9%) and PO 4 3− (−52.5%) concentrations decreased during the dry season. Hydrochemical facies shifted from Cl-NO₃–Ca dominance (93% during the rainy season) toward increased HCO₃–Ca waters during the dry season (21%). Gibbs diagrams indicate a predominance of atmospheric precipitation control (86% rainy season, 79% dry season), with evapoconcentration observed at site L3. PCA highlights a dominant mineralization factor (PC1 explaining 54.76% of the variance, associated with EC, TDS, and major ions), while nutrients and redox-sensitive elements are represented by secondary components. Modified NSF-WQI results identify poor water quality at site L3 during the dry season (Modified NSF-WQI = 43.2), mainly related to elevated EC, NH₄ + , and PO 4 3− concentrations. Discussion These findings demonstrate that seasonal hydrological dynamics combined with anthropogenic inputs, including fertilizers and domestic effluents, significantly influence surface water chemistry in the Bonoua region. This study provides a valuable baseline for monitoring and managing freshwater resources in tropical coastal environments facing increasing environmental pressures.

Introduction High mountain streams are experiencing pronounced shifts in precipitation regimes and water chemistry; however, it remains unclear how organisms inhabiting these systems influence the transfer of chemical elements through food webs. Methods We measured concentrations of potassium and chlorine in algae, grazing mayflies, predatory stoneflies, and Alpine Bullhead ( Cottus poecilopus ) across seasons in an alpine stream. Results Algae exhibited marked seasonal variation, with higher potassium accumulation during the main summer growth period despite relatively stable water concentrations. Grazing mayflies maintained stable potassium levels but showed increased chlorine during colder months when chlorine concentrations in water were elevated. Predatory stoneflies showed only minor seasonal variation, with a slight increase in potassium in winter. The Alpine Bullhead did not exhibit significant seasonal changes in potassium or chlorine accumulation in its skull. Following major flood events, potassium and chlorine concentrations tended to co-vary across trophic levels, whereas under baseflow conditions they often varied independently. Discussion These patterns suggest that different trophic groups regulate element accumulation according to their physiology, life history, and ecological roles. The decoupling of organismal and water chemistry indicates that environmental concentrations alone do not fully explain element distribution within alpine stream food webs. Our findings provide new insights into element dynamics and highlight the importance of biological mediation in high-mountain ecosystems under changing environmental conditions.

Abstract Warming temperatures, heat waves, and altered conditions associated with climate change affect biodiversity and ecological processes across environments, with coastal zones being particularly vulnerable. Biofilm-forming organisms in shallow coastal areas are taxonomically diverse and include bacteria, fungi, and algae that contribute to energy and nutrient cycling along with providing habitats and food for species at the base of the food web. To understand how biofilm-forming organisms respond differently to spatiotemporally changing environmental conditions, seasonal sampling was performed in a Baltic Sea bay that has undergone 50 years of thermal heating, an unaffected nearby control bay, and a temperature gradient along an exposed coastline between the bays. The diversity, composition, and seasonal dynamics of the biofilm communities differed between the three environments largely due to temperature and water chemistry, with biofilms in the heated bay being more similar across seasons compared with the control bay and the gradient, and with prokaryotes exhibiting stronger spatial heterogeneity and seasonal dynamics compared to micro-eukaryotes. In the gradient, the dominating taxonomic groups were distinct, community composition was primarily influenced by seasonal turnover and wave exposure, and alpha diversity of prokaryotes decreased with increasing temperature. Seasonal shifts in the composition of micro-eukaryotic heterotrophs, phototrophs, and mixotrophs differed between environments, with heterotrophs being more dominant at higher temperatures. In conclusion, these contrasting responses indicated that climate warming may disproportionately impact different components of coastal biofilm communities, potentially decoupling key ecological processes and reducing community resilience in Baltic Sea coastal habitats.

The hydrogeochemical characterization of shallow volcanic lakes at the Sete Cidades Volcano (São Miguel, Azores) provides new insights into the processes controlling water chemistry in low-depth lacustrine systems within active volcanic environments. Fourteen lakes (0.6–4 m deep) were sampled during two campaigns (winter 2024 and spring/summer 2025), combining in situ physicochemical measurements and major ion analyses along vertical profiles. The lakes are holomictic, cold (11.3–17.6 °C), slightly acidic (pH 5.66–5.95), and weakly mineralized (EC ~65–69 µS/cm), indicating dilute waters of predominantly meteoric origin. Hydrochemical facies are dominated by Na–Cl type, with strong correlations between chloride and conductivity (r = 0.857), supporting a major contribution from marine atmospheric deposition. To move beyond correlation-based interpretation, Gibbs diagrams and saturation indices (PHREEQC) were applied to constrain the dominant geochemical processes. Most samples plot within the precipitation dominance field, while all calculated saturation indices are negative (SI &lt; 0), indicating undersaturation with respect to carbonate, evaporite, and silicate minerals. These results demonstrate that water chemistry is primarily controlled by atmospheric inputs, with only minor contributions from water–rock interaction and negligible influence of evaporation or mineral equilibrium processes. Seasonal increases in HCO3− and dissolved CO2 at depth suggest enhanced organic matter decomposition during warmer periods, highlighting the role of biogeochemical processes in modulating carbon dynamics in shallow systems. The absence of a clear hydrothermal signature further distinguishes these lakes from deeper volcanic systems in the Azores. This study provides the first integrated hydrogeochemical framework for shallow volcanic lakes in the region, combining classical hydrochemistry with process-based tools. The results establish a quantitative baseline for assessing environmental change and improve the interpretation of external (atmospheric) versus internal (geochemical and biological) controls in volcanic lake systems.

ABSTRACT The effectiveness and efficiency of oil and gas extraction are heavily influenced by the surfactants employed. These chemical agents play a crucial role in boosting productivity by lowering the interfacial tension, enhancing fluid recovery, modifying the wettability of the formation, and minimizing flow resistance. Surfactants can also generate/stabilize foam in those applications where foam is desired, such as water‐sensitive formations. However, water quality varies significantly from site to site, presenting challenges in consistent surfactant performance. This study demonstrates how water chemistry impacts foam properties and interfacial tension using three surfactants: a modified alkyl polyglucoside (Mod APG), sodium lauryl ether sulfate (SLES), and sodium sulfosuccinamate. Among these, the Mod APG has demonstrated strong foaming capabilities, significant reductions in IFT, and high tolerance to diverse water conditions, including salt water and hard water environments.

Background: Fluoride pollution in the mine drainage is of the most serious concern to water chemistry, human health, and aquatic ecosystem. Being present in much higher concentrations than World Health Organization (WHO) guidelines, require efficient and easy-to-implement remediation techniques, particularly in areas affected by phosphate, coal and uranium mines. Aim: In this study, chemical and statistical methods are used to examine the mechanism of fluoride precipitation and present an optimally designed treatment process for mine drainage treatment. Method: Some of the precipitation agents such as calcium, aluminum, and lanthanum were studied at lab scale on batch mode at different pH, dosages, and contact time. the pre- and post-treatment fluoride levels were determined by ion-selective electrodes. From them it was possible to interpret the saturation and precipitation of fluoride minerals as reportedoftheseauthors. thermodynamic computations and kinetic analysis using PHREEQC were runed. Treatment parameter optimization was performed using Response Surface Methodology (RSM), and field verification was carried out for mine water samples from three locations. Results: The optimal conditions of calcium and lanthanum salts removal of fluoride were obtained, and the fluoride removal rate of lanthanum chloride could be up to more than 99%. The best results of precipitation were found at pH 6.5–7.5 and prolonged contact time yielded little increases after 60 min. The experimental results were also in agreement with the thermodynamic, statistical models and then validated in the field (~93% fluoride rejection efficiency to various mine drainage samples). Conclusion: The application of fluoride precipitation for mine water treatment is considered to be a suitable, cost-effective, and flexible process, particularly if it is optimized by statistical and geochemical modeling tools as were used in the present study.

ABSTRACT Time domain airborne electromagnetic (AEM) surveying is a mature geophysical tool for imaging the Earth's shallow subsurface. It produces images of the electromagnetic conductivity structure of the earth, down to depths of a few hundred metres. The AEM method is fast, with rotary‐wing or fixed‐wing aircraft acquiring data at speeds of 100–300 km/h, making it an ideal near‐surface reconnaissance tool. The physics of the AEM method is sensitive primarily to the subsurface conductivity, which is influenced by a range of geological factors such as mineral content, porosity, and water content and chemistry. In addition, the inferred subsurface conductivity depends on the accurate measurement and modelling of airborne transmitter and receiver geometries – a challenging task given the speed of acquisition and variability of wind conditions during an acquisition flight. In this work, we present inferences of the subsurface conductivity over Lake Menindee, New South Wales, Australia, using data from test flights and various AEM systems over a 10‐year period (2014–2024). The lake storage has varied dramatically over this time, and the test flights have coincided with both high and low water levels. While this difference in storage volume undoubtedly influences the near‐surface conductivity, a remarkably consistent interpretation of the regional geology is possible regardless of the hydrologic conditions. While the upper 10 m of the modelled depth sections exhibit the greatest time‐variability in inferred electromagnetic conductivity, the hypothesis that lakebed near‐surface conductivity is significantly correlated with the lake water volume cannot robustly be established. We also provide some information‐theoretic calculations for each inversion result to aid in their quantitative comparison. The implications of our study are that subtle, shallow, hydrogeological changes are difficult to image with repeat AEM overflights from different systems. Conversely, we establish that different AEM systems with minimal extra processing robustly image the regional geo‐electric structure of the near surface, validated by known stratigraphy and associated geological information, as well as borehole conductivity logs.

Invasive riparian plants can alter freshwater ecosystems, yet their impacts in Afromontane rivers remain poorly understood. This study examined the influence of Pteridium aquilinum (bracken fern) on macroinvertebrate communities in the Likhubula River, Mulanje Mountain Forest Reserve, Malawi, using a functional trait–based approach. Macroinvertebrates were sampled monthly during the wet season across three river sections representing invaded (upstream) and uninvaded (midstream and downstream) conditions, alongside measurements of physicochemical parameters. A total of 497 individuals from 30 families were recorded. While taxonomic composition showed limited spatial variation, functional trait composition differed markedly between invaded and uninvaded river sections. Small-bodied and less mobile taxa dominated the bracken-invaded upstream reach, whereas uninvaded sections supported more mobile and generalist taxa. Physicochemical conditions were largely within national standards, and ASPT values indicated good-to-moderate water quality. Overall, functional trait vulnerability was associated with fern invasion, suggesting that P. aquilinum primarily affects macroinvertebrate communities through riparian habitat modification rather than direct changes in water chemistry.

Copper hybrid cluster-engineered cellulose hydrogels enabling coupled ion and water regulation for highly reversible zinc anode.

Aquatic biofilms are an understudied component of northern peatlands and are expected to play a more prominent role in ecosystem processes in areas where aquatic habitat is expanding. The goal of this study was to investigate how hydrologic history influences biofilm diversity and functional genes. This study was conducted in a long-term water table manipulation that simulates drought (lowered water table treatment) and flooding (raised water table treatment) conditions relative to a control treatment (no manipulation). We used a combination of metabarcoding and metagenomic approaches to (1) examine the diversity of eukaryotic algae, cyanobacteria, bacteria and fungi within the biofilm and (2) identify functional genes associated with alternating wet-dry transitional states. Historical flooding, but not drought, led to broad changes in composition and functional genes, especially those associated with carbon metabolism and nitrogen cycling. Differences were related to changes in relative abundance rather than the presence/absence of individual taxa or genes. Hydrologic history influenced community diversity by reducing interspecific competition or by alleviating resource limitation. These findings show that hydrologic history regulates species membership of the community (and thereby associated genes) but differences in water chemistry and interspecific interactions alter the relative abundance of species and their functional potential.

ABSTRACT Groundwater‐dependent wetlands with alkaline water chemistry are typically associated with carbonate rocks such as limestone and dolomite and often display distinctive landforms, soils and biota. A form of such a wetland type occurs in association with alkaline springs and seepages of inland superhumid, maritime southwest Lutruwita/Tasmania. Unlike commonly described calcareous and alkaline wetland types, the Tasmanian examples are characterised by low biomass and minimal organic soil development, despite occurring within landscapes otherwise dominated by ombrogenous blanket peatland. These peat‐bound karstic wetlands are rare, include distinctive geomorphic features and processes and support both a geographically restricted endemic vascular plant flora and living freshwater stromatolites. Collectively these characteristics contribute to the natural values of the Tasmanian Wilderness World Heritage Area. Knowledge about peat‐bound karstic wetlands and their vulnerability to changing fire regimes and climate remains limited. The ecosystem processes that inhibit peat accumulation and prevent woody plant invasion are poorly known but essential for the persistence of this rare ecosystem. Here we examine the distribution and morphology of peat‐bound karstic wetlands and present results of nine years of vascular plant monitoring. We found peat‐bound karstic wetlands are restricted to locations where calcium rich alkaline groundwater discharge is sufficient to prevent neutralisation by acidic surface water. They are lotic wetlands that have a frequent but intermittent (day‐month) shallow flow and comprise poorly developed stream beds, associated alluvial deposits and pools. Vegetation along permanent transects showed either little change or minor increases in the abundance of acidic peatland species. Ad hoc observations and aerial imagery suggest that these wetlands are subject to infilling and colonisation by species from adjacent vegetation over longer time scales. Fire frequency may restrict plant growth and woody plant colonisation, while dissolution and flushing of organic matter by flow of alkaline groundwater may be important in preventing peat accumulation.

Mitigating acid sulfate soil development in sediment addition projects through application of sediment amendments.

Tailings reclamation is a significant challenge facing the oil sands industry. There are 1.4 billion m 3 of fluid fine tailings (FFT), a slurry waste stream generated from oil sands surface mining, awaiting reclamation. Pit lakes may be a suitable reclamation option, however further evaluation is required before pit lakes receive regulatory approval as an FFT reclamation method. FFT destined for pit lakes may be treated (with alum and polyacrylamide) and contain residual hydrocarbons. This study is the first publicly available comparison of the behavior of untreated versus treated FFT in pit lakes. Forty columns were monitored for 540 d under anaerobic conditions to evaluate the effects of tailings treatment, hydrocarbon amendments, and temperature (10 °C and 20 °C) on the biogeochemical and geotechnical behavior of FFT in pit lakes. Although tailings treatment aims to improve dewatering performance, this study found that treatment significantly reduced dewatering and consolidation. This highlights challenges in achieving optimal flocculation conditions, even in a controlled laboratory setting. Tailings treatment and hydrocarbon amendments significantly enhanced sulfate reduction, which was the dominant microbial process. Treated FFT had a greater abundance of known sulfate reducing bacteria and more extensive sulfate reduction than untreated FFT, while hydrocarbon amendments quickly led to >99% sulfate reduction. Sulfate reduction generated dissolved sulfide species throughout the columns and led to significant increases in alkalinity and CO 2(g) . Divalent cations were subsequently impacted and presumably precipitated as carbonate minerals. These pore water chemistry changes resulted in higher tailings solids contents, leading the authors to propose a new bioconsolidation pathway for FFT via sulfate reduction. • Coagulation/flocculation treatment decreased tailings dewatering and consolidation • Sulfate reduction was significantly enhanced by tailings treatment and hydrocarbons • Treated tailings had a greater abundance of sulfate reducing bacteria • Hydrocarbon amendments led to rapid and > 99% sulfate reduction • Sulfate reduction increased alkalinity and CO 2 and decreased cation concentrations

Managed environmental flows and tributary inflows differently stimulate bacterial production and change microeukaryote communities in a regulated river.